Genetics and Heredity

Heredity The passing of traits from parent to offspring (children) Can be by sexual or asexual reproduction.

Asexual vs Sexual Reproduction

Trait a distinguishing quality or characteristic, typically one belonging to a person. Inherited trait: in humans, eye color is an example of an inherited characteristic: an individual might inherit the "brown-eye trait" from one of the parents. Inherited traits are controlled by genes and the complete set of genes within an organism's genome is called its genotype.

Allele An allele is an alternative form of a gene (one member of a pair) that is located at a specific position on a specific chromosome. These DNA codings determine distinct traits that can be passed on from parents to offspring through sexual reproduction.

Dominant Alleles A trait that covers over or dominates another form of that trait. Trait that always shows up, even when only one of the two alleles is in the dominant form. Shown by a capital letter B= BROWN T=Tall

Recessive Allele A trait that is covered over, or dominated by another form of that trait and seems to disappear Hidden when the other copy of the gene contains the dominant allele A recessive allele shows up only when there is no dominant allele present Shown with a lower case letter b=blue t=short

Dominant = capital letter Recessive = lower case letter

Phenotype vs Genotype Phenotype: an organism’s outward physical appearance and behavior Genotype: an organism’s genetic makeup

Homozygous Both alleles (forms of the gene) are the same When offspring inherit two dominant genes (one from each parent) they are said to be homozygous dominant (BB, TT, CC) When offspring inherit two recessive genes (one recessive gene from each parent) they are said to be homozygous recessive (bb, tt, cc)

Heterozygous When alleles occur in different forms When offspring inherit one dominant gene and one recessive gene (Bb, Tt, Cc)

Who was Gregor Mendel? Gregor Mendel was an Austrian monk who discovered the basic principles of heredity through experiments in his garden. Mendel's observations became the foundation of modern genetics and the study of heredity, and he is widely considered a pioneer in the field of genetics.

What is GENETICS? The study of how traits are inherited through the interactions of genesis father’s garden

How can we determine what traits will show up in an organism PUNNETT SQUARE: a tool that predicts the probability of certain traits in offspring that shows the different ways alleles can combine A way to show phenotype & genotype A chart that shows all the possible combinations of alleles that can result when genes are crossed.